After first loading the 767 into FSX, if the Speed Indicator reads 000, and the Altitude Indicator reads 00000, then try reloading the 767.

It might simply be that your eyepoint is INSIDE the headrest on the Pilots Chair (this will prevent you from interacting with any buttons and switches in the VC, but have no affect on the 2D panels). Use CTRL+BACKSPACE (the default keyboard command) to move the eyepoint forward until it is outside the headrest, then try rotating the knobs.

If the Speed Indicator reads 200, and the Altitude Indicator reads 10000, but the knobs still don't work after moving the eyepoint, then I suggest you reinstall the 767 using the Repair option. If your OS is Vista/Win7/Win8, then make sure you use the Run as administrator option.